Selenium-containing glass



Patented Jan. 14, 1947 2,414,413 SELENIUM-CONTAINING cuss Arnold E. Pavllsh and Chester R. Austin, Columbus, Ohio, assignors toBattelle Memorial Institute, Columbus, Ohio, a corporation of Ohio V No Drawing. Application July 28, 1942, Serial No. 452,620

18 Claims. (Cl. 10652) Our invention relates to selenium-containing glass. It has to do, method of and means more particularly, with a for retaining selenium in glass during processing from the batch state to the time of fabrication of the final article. It

has to do, more specifically,

reducing agents, su

loys containing silicon, to

aid in the retention Selenium is used decolorizer, usually oxide, to neutralize the from iron oxide in selenium pink glass; other ingredients, for ruby or other colored'glasses. selenium commonly added for with the addition of ch as silicon, silicides or althe glass batch which of selenium during the melting and fining operations.

in the glass industry as a in conjunction with cobalt greenish tint resulting the glass, for producing and, in conjunction with the production of selenium The amount of decolorization is 0.1 to 0.3 pound per ton of glass; for pink glass about 2 to 3 pounds per ton of glass; for ruby colored glass about and for other colored glasses pounds per ton of pounds per ton of glass; from 0,5 to 20 glass, depending upon the particular color or shade desired.

With the standard methods of adding selenium to glass batches, a large percentage of the selenium volatilizes and fining operations.

excess of selenium the batch in order and is lost in the melting Therefore, an appreciable must be added originally to to have the desired amount in the final glass. This is true regardless of the form in which the selenium is added. I Because of the large amount of selenium used in tance to retain the glass batch used for Virtually all comm the selenium losses selenium ruby glass, it

is of special imporselenium incorporated in a making this type of glass. ercial selenium ruby glasses in small day tanks where are less than in the large,

usually more economical, open-flame continuous tank melting units.

It is also quite common to use expensive base glasses, containing zinc oxide, for this kind of glass owing to the fact that these base glasses w ill better retain the selenium.

It is under these conditions that it is necessary to add 20 pounds or more oi. selenium per ton of glass batch to obtain the necessary selenium retention for selenium ruby glass production.-

out excessive loss of selenium.

Another object of our invention is to provide a glass batch of the nature indicated in the preceding paragraph and wherein it is not necessary to use expensive base the selenium.

Still another object of our invention is to retain selenium eilectively in glass batches without depending upon a reducing gaseous atmosphere in the 'i'umace above the glass during the melting and fining operations.

We have found that substantial economies in selenium requirement can be realized by adding small percentages of silicon, silicides, or alloys containing silicon, along with the selenium in the glass batch. The addition of any of these substances results in increased selenium recovery. In addition to increasing selenium recovery, silicon additions-also make the production of selenium-containing glass, particularly selenium ruby glass, in continuous tanks economically feasible. Furthermore, it is not necessary to use expensive base glasses, for the purpose of more eifectively retaining the selenium, ium-containing glass.

Only small percentages of silicon are required to produce the desired eiiect. The data given in the following. table, show the improvements in selenium recoveries obtained by introducing siliin producing the selenglasses in order to retain I v 4 con-containing materials into the glass batch Additions made to each batch. temperature along with the selenium addition. I after charging, and melting times were as Efiect of silicon additions on selenium recovery x323? Silicon addition Selenium Selenium Test N0. s c inghaesgi telegram,

Se CdS Kind :5 content. De 08 percent 1 Based on weight of glass batch. 1 Theoretical silicon content. 1 t

The above data were obtained from glasses follows: made by pouring 500-gram batches into crucibles j at 2700 F., the batches being heated to 2700 F., Additions to glass Tempew held approximately two hoursv at that tempera- Melt N0 batchipercent ture after ture, and poured out or fabricated into glass g fg articles I Se CdS FeSi (90% Si) Various forms of silicon can be used to retain H selenium ffectively, as shown in the foregoing Q: g :2- g. gig table, but the effectiveness varies with the par- 3. .35 .0 .1 5 21175. 15 ticular form in which the silicon is added. Metv allurgical retro-silicon, 90 percent grade, is par- A soft flame was employed in the day tank ticularly advantageous from the standpoints of which was fired with natural gas. Such a flame cost, ease of handling, and availability. is considered to maintain a slightly reducing at- We prefer to add silicon in amounts ranging .mospherein the tank. The final melting temfrom 0.10 to 1 percent by weight regardless of perature was 2750 F. in all of the tests. the form in which it is added. The amount of The recoveries of selenium, cadmium, and sul-' reducing agent added, however, depends upon -fur'were as follows:

the amount of selenium added to the batch as well as upon the amount of selenium desired in I C f an 1 r the final glass. The selenium present in the glass 21 33: pz r cgnt Selenium Silicon batchwill usually range from eflective amounts 53mg: $233? up to 1 percent by weight. I Se Cd s I The glass batches used in the tests referred to in the above table were the ordinary soda-lime- 1 0.49 0.01 0.04 40 0.00 I silica types. The usual range of base glass comgljjjzjijj 4 :53 3% g position which may be used in this invention is about as follows: 1 Based on weight of glass batch. weight Selenium recoveries of less than 5 percent are Ingram percent common in commercial production without silicon additions. In general, small silicon additions 09-74 made it possible to reduce the seleniumaddition i H 55 to about one-third or less of the amount normally required. I 7-13 In selenium ruby glass, made from a soda-lime silica type of batch, the selenium recovery in Howeven-it is to be understobd that many creases as the silicon addition is increased. Howbase glasses are suitable for the practice of this ever at the m tune thePadmmm recovery invenflon decreased. It is therefore important to balance The effectiveness of silicon additions, in retainw addition of selfiamum' cadmium Sulfide d mg selenium, was also shown by three 3000 silicon so as to ach1eve the desired result. The

pound n-, of a soda-nme-suica base glass made selenium added will range from effective amounts in commercial glass tank, to 1 percent by weight, the cadmium sulfide added The raw batch gomposltion f the base glass will range from effective amounts to 1 percent was as f 11 w by weight, and the silicon added will range from 1 effective amounts up to 1 percent by weight.

Ingredient Pounds The final glass will have present in it silica, 7 a portion of which will have been produced by Band 1,770 the oxidation of metallic siliconoriginally added.

to the glass batch.

It will be apparent from the above that our invention minimizes the loss of selenium from glass batches during the melting and fining operations. By incorporating silicon in glass batches, according to our invention, the batch can be melted and fined in continuous tank units without excessive loss of selenium. This is particularly important in the production of selenium ruby glass. Furthermore, because of our invention, it is not necessary to employ expensive base glasses in producing ruby glass. our invention, the selenium can be retained effectively in glass batches without depending upon a reducing gaseous atmosphere in the furnace above the glass during the melting and fining operations.

Various other advantages will be apparent from the preceding description and the following claims.

Having thus described our invention, what we claim is:

1. A method of retaining selenium in glass during processing from the batch stage to the time of fabrication of the final article which comprises incorporating in the glass batch in conjunction with the selenium a material selected from the group consisting of silicon, silicides, silicon carbide, and alloys containing silicon,

2. A method of retaining selenium in selenium ruby glass during processing from the batch stage to the time of fabrication of the final article which comprises incorporating in the glass. batch in conjunction with the selenium a material selected from the group consisting of silicon, silicides, silicon carbide, and alloys containing silicon.

3. Amethod of adding selenium to glass which comprises adding the selenium in conjunction with a material containing metallic silicon.

4. A method according to claim 3 wherein the material is ferrosilicon.

5. A method of increasing. the recovery of selenium in glass which comprises adding to a glass batch selenium together with a material containing metallic silicon, the silicon addition being made in amounts ranging from efiective amounts up to 1.0 per cent of the glass batch.

6. A method of making a silica-containing selenium glass wherein a portion of the silica has According to been produced by the oxidation of metallic silicon originally added to the glass batch.

'7. A method of increasing the recovery of selenium in glass which comprises adding to a glass batch selenium in efiective amounts up to 1 per cent, together with silicon in effective amounts up to 1 per cent.

8'. A method according to claim '7 wherein cadmium sulfide is also added in effective amounts upto 1 per cent. g V

9. A glass batch containing selenium and a material selected from the group consisting of silicon, silicides, silicon carbide, and alloys containing silicon.

10. A glass batch containing. selenium in amounts ranging from effective amounts to 1 per cent and a material selected from the group consisting of silicon, silicides, silicon carbide, and alloys containing silicon in effective amounts up to '1 per cent.

11. A glass batch according to claim 10 which contains cadmium sulfide in efiective amounts up to 1 per cent.

12. A glass batch containing selenium and a material containing metallic silicon.

13. A glass batch according to claim 12 wherein the material is ferrosilicon.

14. A glass batch containing selenium together with a material containing metallic silicon, said material being present in amounts ranging from effective amounts up to 1 batch.

15. A method of adding selenium to glass which comprises adding the selenium in conjunction with an oxidizable silicon-containing material.

16. A glass batch containing selenium and an,

oxidizable silicon-containing material.

17. A glass batch containing selenium and ferrosilicon.

. 18. The method of adding selenium to glass which comprises adding the selenium in conjunction with a material selected from the group consisting of silicon, silicid s, silicon carbide, and alloys containing silicon.

' ARNOLD E. PAVLISH. CHESTER R.,AUSTIN.

per cent of the glass 

